Lattice data suggests that the QGP formed at high-energy heavy-ion collisions is not a fully conformal fluid, and bulk viscosity, which is a purely non-conformal effect, is needed for the precise extraction of the shear viscosity of the QGP [1]}. Hydrodynamics including non-conformal effects successfully describes the smaller system such as p-Pb [2]} and p-p [3]}, [4]} collisions [5]}. The original duality can be extended to the theories more similar to QCD or QGP using the well-known top-down [6]}, [7]}, [8]} or a bottom-up [9]}, [10]} approaches.
